CN1042675A - Suspended crystallization method for producing electrode material of tungsten-rare earth oxide - Google Patents
Suspended crystallization method for producing electrode material of tungsten-rare earth oxide Download PDFInfo
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- CN1042675A CN1042675A CN 88107860 CN88107860A CN1042675A CN 1042675 A CN1042675 A CN 1042675A CN 88107860 CN88107860 CN 88107860 CN 88107860 A CN88107860 A CN 88107860A CN 1042675 A CN1042675 A CN 1042675A
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- rare earth
- earth oxide
- tungstate solution
- ammonium tungstate
- reduction
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Abstract
The present invention is the new technology of producing electrode material of tungsten-rare earth oxide.Its principal character is to be raw material with ammonium tungstate solution and rare earth oxide, by suspended crystallization method, makes ammonium paratungstate-rare earth oxide crystal, through operations such as reduction, pre-burning, incipient fusion processing, finally makes goods.The present invention compares with existing more excellent wet method, has simplified two big operations, has saved man-hour, has reduced energy consumption, and has improved productivity ratio, and eliminated the NO that emits in the technical process
2, SO
2Deng environment and human body are had harm gas.Rare earth oxide is evenly distributed in matrix tungsten, disperse, electrode arc excellent performance, long service life.
Description
The invention belongs to the method for making goods by metal dust.Mainly be applicable to and produce the electrode material of tungsten-rare earth oxide that gas is protected usefulness such as weldering, plasma cutting or steel-making.
At present, the electrode material of tungsten-rare earth oxide of usefulness such as production argon arc welding both at home and abroad, plasma cutting, steel-making all adopts powder compaction, sintering and deformation processing to form.Batching in its technical process, method for mixing generally all adopt " dry method " or " wet method "." dry method " is tungsten powder and rareearth oxidate powder to be put together mix mutually.The disadvantage of this method is in the mechanical batch mixing process that reaches more than 20 hours, spheroidizing of powder, and the tungsten powder surface oxidation, the active reduction, unfavorable to later sintering; Simultaneously, because the wearing and tearing of mixing machine inwall as impurity, certainly will be sneaked in the material, the purity of electrode material is reduced; In addition, this method is difficult to reach the even of micro components." wet method " is that tungsten powder (perhaps its oxidate powder) is joined in the aqueous solution of rare earth salts (nitrate, sulfate), through heating, stirring, evaporation and concentration, oven dry, forms the cladding powder, makes electrode material through thermal decomposition and reduction again.This method operation is various, and energy consumption is big, and in oven dry of cladding powder and thermal decomposition process NO is arranged
2(NO), SO
2Pernicious gas is separated out.
The object of the present invention is to provide a kind of manufacture method of new electrode material of tungsten-rare earth oxide.This method not only operation is simple, and energy consumption is little, and cost is low; And powder surface is active big, the purity height, and no pernicious gas is separated out, prepared electrode arc excellent performance, electrode life is long.
The main technique measure of this method is to adopt suspended crystallization method, preparation ammonium paratungstate-rare earth oxide crystal, be about to rare earth oxide and join in the ammonium tungstate solution for preparing, heating makes its evaporation then, when evaporation and concentration to original volume 50～70% the time, because the volatilization of part ammonium, solution becomes neutrality gradually, and forms the paratungstate ion therein, the paratungstate ion combines with ammonium and generates the little order of ammoniumparatungstate crystal of solubility, is precipitated out from mother liquor.In crystallization process, the rare earth oxide that adds can be used as heterogeneous center, it is nucleus, the ammonium para-tungstate crystal body is that core is carried out crystallization with this nucleus, it is ammonium paratungstate crystallization in the above, perhaps in crystallization process, rare earth oxide is rolled in the order of ammoniumparatungstate crystal the inside, perhaps sticks in its acupuncture point, on the surface.In addition, at 5(NH
4)
2O12WO
35H
2O → W
4O
11→ WO
2In the serial reduction process of → W, the rare-earth oxidation deposits yields delicate physical-chemical effect.Thus, can obtain microcosmic evenly, the tungsten-rare earth oxide mixed-powder of disperse.The electrode made from this powder has that the starting the arc is easy, and burn out rate is low, characteristics such as the stable and long service life of arc electrode.
The technological process of this method is:
Batching → evaporative crystallization → mechanical batch mixing → prereduction → secondary reduction → die mould → pre-burning → incipient fusion → processing.
The concrete operation of each of above-mentioned technological process is as follows:
(1) batching
The primary raw material of this method is ammonium tungstate solution and RE oxide powder.
Ammonium tungstate solution is formulated by wolframic acid, deionized water and ammoniacal liquor (proportion γ=0.901～0.910), and its proportioning is:
Wolframic acid: deionized water: ammoniacal liquor=(70～90) kilogram: (110～130) rise: (80～100) rise
The addition of rare earth oxide is relevant with the proportion of ammonium tungstate solution, and accompanying drawing 1 is the rare earth oxide amount K(gram that need to add in every liter of ammonium tungstate solution) with the relation curve of ammonium tungstate solution proportion γ.Need the total amount G(gram of the rare earth oxide of adding) be
G＝K·V
V is the volume (liter) of ammonium tungstate solution in the formula
According to proportion relation, rare earth oxide is poured in the ammonium tungstate solution that has stirred.
(2) evaporative crystallization
Solution (ammonium tungstate solution that the adds rare earth oxide) pressurized, heated for preparing is stirred evaporation.Air pressure is controlled between 1.5～2.5 atmospheric pressure, and heating-up temperature is 75-85 ℃, and the heating mixing time is 1.5～3 hours.
When heating evaporation to the ratio of the surplus liquid 1.065-1.075 gram per centimeter that weighs
3The time, stop heating, add cold deionized water subsequently, stir half an hour, behind the precipitation certain hour, the clarified solution above extracting out after the washing, then obtains containing the order of ammoniumparatungstate crystal of rare earth oxide again.This crystal is placed oven dry in the drying baker, bake out temperature≤200 ℃.After the V-type batch mixer mixes, survey its particle mean size and rare earth oxide content.
(3) prereduction
Prereduction is to carry out in the continuous reduction furnace of hydrogen shield, and Control for Kiln Temperature is at 400～500 ℃, and temperature retention time is 1～2 hour, and the prereduction product is W
4O
11CeO
2Powder.
(4) secondary reduction
In the continuous reduction furnace of logical hydrogen, carry out secondary reduction.Reduction high-temperature region temperature is 800-950 ℃, and temperature retention time is 3～4 hours, makes W-CeO thus
2Powder.
(5) compression moulding
The powder ECDC boat batch mixer of secondary reduction sieves after mixing.Powder after sieving adds binding agent, to be mixed evenly after, on forcing press, be pressed into required shape.
The pressure of its compacting be 3～4 ton forces/centimetre
2;
The addition of binding agent is 5 milliliters of/kilogram powder;
The composition proportion of binding agent is:
Glycerine: alcohol=2: the 1(volume ratio)
(6) pre-burning
The blank of compression moulding carries out pre-burning in logical hydrogen molybdenum wire furnace.Calcined temperature is 1100-1250 ℃, temperature retention time 40 minutes.
(7) incipient fusion
The blank of pre-burning is carried out incipient fusion on the logical hydrogen incipient fusion machine of bell-type water-cooled.The technological parameter of incipient fusion is: 15～20 minutes heating-up times; Insulation electric current 2650-2850 ampere, temperature retention time 20 minutes; The density d of blank should be greater than 17.4 gram per centimeters behind the incipient fusion
3
(8) processing
Base bar behind the incipient fusion through the drawing processing of swaging, is carried out homogenizing annealing and the suitably stress relief annealing of passage subsequently, finally make the electrode material of tungsten-rare earth oxide of required size.
Adopt this method to produce electrode material of tungsten-rare earth oxide and have tangible economic benefit and social benefit.
Compare with existing more excellent wet processing, simplified two big procedures, promptly saved the roasting and the WO of ammonium paratungstate
3Mix stirring mutually with rare earths salt and boil dry operation, saved man-hour very significantly, reduced energy consumption; Improve productivity ratio, eliminated the NO of rare-earth salts in roasting and reduction process
2, SO
2Deng pernicious gas to environment and man body pollution; Because the blank processing characteristics that this method makes is good, the processing recovery rate improves 2～5% than current technology.
Description of drawings and embodiment
Accompanying drawing 2 is a WCe electrode bar vertical section optics metallograph.A, B, C are respectively 3,2 millimeters of the present invention's, wet method, the obtained φ of dry method WCe20 WCe20 WCe15 electrode bar vertical section optics metallograph (multiplication factor is respectively 400X, 200X, 200X) among the figure.Find out CeO of the present invention by figure
2The distribution of particle in matrix tungsten is all than more even, the disperse of other two kinds of technologies.
Embodiment
Adopt ammonium tungstate and CeO
2Powder is produced WCe
20Electrode material.
The proportion γ of used ammonium tungstate solution=1.28 gram per centimeters
3, volume is 60 liters; The granularity of final WCe powder is controlled at 2.00 μ, CeO in the WCe powder
2Content be 2.3%, with reference to the accompanying drawings 1, CeC
2The adding total amount be 378 the gram.
Ammonium tungstate solution and CeO
2Powder added thermal agitation 1.5 hours, when proportion is 1.06～1.08 gram per centimeters after mixing under 2.0 vapour pressures
3The time, stop heating, add 30 liters of cold deionized waters, stirred 30 minutes, deposit 45 minutes.
Extract supernatant out, add 30 liters of cold deionized waters again, stirred 15 fens, deposit 120 fens.
Drain upper clear liquid, take out ammonium paratungstate-CeO
2Crystal, thoroughly oven dry in 150-200 ℃ * 2 hours is sieved in baking oven, and machine mixed 4 hours.
In the pipe furnace of logical hydrogen, 400-500 ℃ of following prereduction makes W
4O
11-CeO
2Powder.
In logical hydrogen five warm areas five pipe furnaces, carry out the two-stage secondary reduction under 600-650 ℃ and 800-850 ℃, make W-CeO
2Powder.
At 3 tons/centimetre
2Press forming under the pressure (12 * 12 * 400 millimeters) blank, pressed compact is in the pre-burning in 1100-1200 ℃ * 30 minutes of logical hydrogen molybdenum wire furnace back warp.
Presintered compact leads to the sintering of directly switching on the hydrogen incipient fusion in the bell-type water-cooled, and incipient fusion electric current A=2700 ampere is incubated 20 fens.
The incipient fusion bar is through swage machining and drawing processing, when being worked into 95 millimeters of φ, carries out homogenizing annealing and the suitably stress relief annealing of passage later on, processes the electrode stem material and the silk material of various sizes.
Claims (6)
1, a kind of reparation technology of electrode material of tungsten-rare earth oxide, comprise operations such as ammonium paratungstate preparation, mechanical batch mixing, reduction, pre-burning, incipient fusion, processing, it is characterized in that adopting suspended crystallization method to produce ammonium paratungstate-rare earth oxide crystal by ammonium tungstate solution and rare earth oxide; In reduction process, adopt twice reduction, i.e. prereduction and secondary reduction.
2, technology according to claim 1 is characterized in that ammonium tungstate solution made by wolframic acid, deionized water and ammoniacal liquor, and its proportioning is:
Wolframic acid: deionized water: ammoniacal liquor=(70～90) kilogram: (110～130) rise: (80～100) rise
3, technology according to claim 1, its feature is definite by following formula in the addition of rare earth oxide, promptly
G＝K·V
The total amount of the rare earth oxide (gram) of G for needing to add in the formula, K is the rare earth oxide amount (gram) that every liter of ammonium tungstate solution need add, V is the volume (liter) of ammonium tungstate solution.
4,, it is characterized in that rare earth oxide amount K that every liter of ammonium tungstate solution need add is by ammonium tungstate solution proportion γ and CeO according to claim 2 and 3 described technologies
2The relation curve of amount is determined.
5,1,2 and 3 described technologies as requested needing in the mixed evaporation and crystal process of ammonium tungstate solution and rare earth oxide is characterized in that the pressurized, heated evaporation; When being evaporated to surplus liquor ratio heavily is 1.065～1.075 gram per centimeters
3The time, stopping heating, and successively add cold deionized water washing for twice, post precipitation is removed clarified solution, promptly obtains containing the order of ammoniumparatungstate crystal of rare earth oxide.
6, technology according to claim 1, the prereduction temperature that it is characterized in that twice reduction is 400～500 ℃, temperature retention time 1～2 hour; The high-temperature region temperature of secondary reduction temperature is 800～950 ℃, temperature retention time 3～4 hours.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 88107860 CN1012478B (en) | 1988-11-17 | 1988-11-17 | Suspended crystallization method for producing electrode material of tungsten-rare earth oxide |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 88107860 CN1012478B (en) | 1988-11-17 | 1988-11-17 | Suspended crystallization method for producing electrode material of tungsten-rare earth oxide |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1042675A true CN1042675A (en) | 1990-06-06 |
| CN1012478B CN1012478B (en) | 1991-05-01 |
Family
ID=4834815
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN 88107860 Expired CN1012478B (en) | 1988-11-17 | 1988-11-17 | Suspended crystallization method for producing electrode material of tungsten-rare earth oxide |
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| Country | Link |
|---|---|
| CN (1) | CN1012478B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1060709C (en) * | 1998-06-25 | 2001-01-17 | 北京工业大学 | Ternary compound rare-earth tungsten electrode material and its preparing process |
| CN102626785A (en) * | 2012-04-27 | 2012-08-08 | 北京科技大学 | Preparation method for rare earth oxide doped tungsten powder |
-
1988
- 1988-11-17 CN CN 88107860 patent/CN1012478B/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1060709C (en) * | 1998-06-25 | 2001-01-17 | 北京工业大学 | Ternary compound rare-earth tungsten electrode material and its preparing process |
| CN102626785A (en) * | 2012-04-27 | 2012-08-08 | 北京科技大学 | Preparation method for rare earth oxide doped tungsten powder |
Also Published As
| Publication number | Publication date |
|---|---|
| CN1012478B (en) | 1991-05-01 |
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